Santana calls Finn "Frankenteen". This is a nod to his Twitter screenname, which is also "Frankenteen".
When Doris Sylvester is talking about her Nazi hunting she mentions the name Mengele. Dr. Joseph Mengele, known as the "angel of death" was the doctor at Auschwitz-Birkenau. He decided which of the new arrivals would go to the right (life) or to the left (death in the gas chambers). He was infamous for conducting grisly "science experiments" with twins and other prisoners.
Both Matthew Morrison and Carol Burnette starred together in Once Upon a Mattress (2005).
Carol Burnett and Jane Lynch both played Miss Hannigan in the musical Annie. Burnett in the film and Lynch on Broadway.